An exchange transfusion is a medical treatment in which apheresis

Apheresis

Apheresis is a medical technology in which the blood of a donor or patient is passed through an apparatus that separates out one particular constituent and returns the remainder to the circulation...

 is used to remove one person's red blood cell

Red blood cell

Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...

s or platelet

Platelet

Platelets, or thrombocytes , are small,irregularly shaped clear cell fragments , 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes.  The average lifespan of a platelet is normally just 5 to 9 days...

s and replace them with transfused

Blood transfusion

Blood transfusion is the process of receiving blood products into one's circulation intravenously. Transfusions are used in a variety of medical conditions to replace lost components of the blood...

 blood products. Exchange transfusion is used in the treatment of a number of disease

Disease

A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...

s, including:

• Sickle cell disease
• Thrombotic thrombocytopenic purpura
  Thrombotic thrombocytopenic purpura
  Thrombotic thrombocytopenic purpura is a rare disorder of the blood-coagulation system, causing extensive microscopic thromboses to form in small blood vessels throughout the body...
  
   (TTP)
• Hemolytic disease of the newborn
  Hemolytic disease of the newborn
  Hemolytic disease of the newborn, also known as hemolytic disease of the fetus and newborn, HDN, HDFN, or erythroblastosis fetalis, is an alloimmune condition that develops in a fetus, when the IgG molecules produced by the mother pass through the placenta...
  
  

Description

An exchange transfusion requires that the patient's blood can be removed and replaced. In most cases, this involves placing one or more thin tubes, called catheters, into a blood vessel. The exchange transfusion is done in cycles: each one usually lasts a few minutes.

The patient’s blood is slowly withdrawn (usually about 5 to 20 mL at a time, depending on the patient’s size and the severity of illness). An equal amount of fresh, prewarmed blood or plasma flows into the patient's body. This cycle is repeated until the correct volume of blood has been replaced.

After the exchange transfusion, catheters may be left in place in case the procedure needs to be repeated.

In diseases such as sickle cell anemia, blood is removed and replaced with donor blood.

In conditions such as neonatal polycythemia, a specific amount of the child’s blood is removed and replaced with a normal saline solution, plasma, or albumin (the clear liquid portion of blood). This decreases the total number of red blood cells in the body and makes it easier for blood to flow through the body.

Risks

General risks are the same as with any transfusion. Other possible complications include:

• Blood clots
  Thrombosis
  Thrombosis is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel is injured, the body uses platelets and fibrin to form a blood clot to prevent blood loss...
  
  
• Changes in blood chemistry (high or low potassium
  Potassium
  Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
  
  , low calcium
  Calcium
  Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
  
  , low glucose
  Hypoglycemia
  Hypoglycemia or hypoglycæmia is the medical term for a state produced by a lower than normal level of blood glucose. The term literally means "under-sweet blood"...
  
  , change in acid-base balance in the blood )
• Heart and lung problems
• Infection (greatly decreased risk due to careful screening of blood)
• Shock due to inadequate replacement of blood

Recovery

The infant may need to be monitored for several days in the hospital after the transfusion, but the length of stay generally depends on the condition for which the exchange transfusion was performed.